Software bugs may indicate a lack of expertise or lower quality, but they always drive improvement. “Bug” has become a common IT term in the 20th century. Today, its usage is so mundane that the entire defect lifecycle is simplified into three stages:
- Bugs appear (why?).
- Bugs are fixed (how?).
- A bug no longer exists (will it come back?).
But for software testing services, it’s more complicated than “squishing an insect”. Developers and QA teams need to locate, define, replicate, resolve, and revise an issue to deem it eliminated. So let’s dive into the intricacies of software bugs and their untimely deaths.
What Is a Software Bug?
Across many definitions, the common notion is that a bug is a defect or error that leads to undesired system behavior. Why a defect OR an error? If we dive into the technicalities, there’re some distinct traits for these labels.
A Bug Is a Code Flaw
A bug is a general term used to describe any unexpected or unintended behavior in software. It refers to a flaw or mistake in the code that causes the software to deviate from its intended functionality.
Example: a user clicks on a “Submit” button in a web application, but the app crashes instead of processing the submission.
A Defect Is the Contrasting Outcomes
A defect is a specific type of bug that typically implies a failure of the software to conform to its specifications or requirements.
Example: a financial software application is supposed to calculate compound interest accurately based on user inputs, but it miscalculates the interest due to a formula error.
An Error is a Human-Driven Mistake
An error typically refers to a mistake made by a human programmer during the coding process. It can encompass syntactical errors, logical errors, or incorrect implementation of algorithms.
Example: a navigation app guides users to take the longest route to their destination due to a programming mistake in the algorithm that calculates the shortest path.
An Issue Is an Umbrella Term
“Issue” is a broader term encompassing bugs, defects, and other problems that may arise during software development, testing, or usage. It can refer to any situation that requires attention.
Example: users of a mobile app report that the app takes an unusually long time to load certain pages. This performance slowdown is an issue.
Everyone should be aware of such differentiating nuances, just in case. But don’t rush and put a printout on your wall. Typically, QA teams go with “bugs” and avoid assigning blame by using “error” or overthinking the “true definition of an issue”.
Why Does Software Have Bugs?
Software bugs are an inherent and inevitable aspect of software development. Despite the efforts of skilled developers and rigorous testing methodologies, bugs can emerge for various reasons.
Complex & Evolving Requirements
Software development often begins with requirements (specifications that define a product) that can change over time. As projects progress, new features may be added, existing functionalities modified, or user expectations adjusted. This dynamic nature of requirements introduces the potential for misinterpretation, overlooked scenarios, and unintended interactions.
Human Error
Software development is a collaborative and creative endeavor involving human programmers who write and maintain code. Syntax errors, logical errors, and incorrect assumptions about how different parts of the software should interact can lead to unintended software behaviors.
Complexity & Interdependencies
Modern software is complex, often composed of numerous components, modules, libraries, and external APIs. As systems grow in size and complexity, it becomes challenging to anticipate all possible interactions between different parts. Changes made to one software aspect can inadvertently affect others.
Hardware & Environment Variability
Software often runs on various hardware configurations and environments, each with its own unique characteristics. Differences in operating systems, hardware components, network conditions, and user preferences can lead to software behaving illogically or encountering compatibility issues.
Tight Deadlines & Pressure
In today’s fast-paced software development landscape, the pressure to deliver products quickly to meet market demands is overwhelming. Time constraints can force developers to make trade-offs between thorough testing and timely delivery, potentially leading to the release of software with unresolved bugs.
Changing Technologies & Platforms
The software development ecosystem constantly evolves. And new programming languages, frameworks, libraries, and tools arise regularly. Migrating software to new technologies or platforms can introduce unforeseen issues due to differences in behavior, APIs, or underlying architecture.
Communication & Collaboration Challenges
Effective software development requires clear communication and collaboration among team members. Miscommunication or lack of coordination can lead to misunderstandings, differing interpretations of requirements, and missed opportunities for bug prevention.
External Factors
All software interacts with external services, APIs, databases, and third-party components. Changes or disruptions in these systems, such as updates to APIs or server outages, can lead to the emergence of bugs.
It is impossible to eliminate bugs entirely due to thousands of impact points. And developers and QA engineers strive to bring software to its optimal level, not the elusive and subjective perfection.
How to Identify a Bug?
You’ve heard that QA engineers are vital in locating bugs before the product reaches the end users. But how exactly do they do this?
How Do QA Engineers Find Bugs?
QA engineers are like digital detectives, meticulously examining the software’s nooks and crannies to uncover any irregularities. They employ various strategies and techniques to identify bugs, using, among the others:
- Testing scenarios – QA engineers meticulously follow predefined testing scenarios and use cases to simulate real-world interactions with the software. They ensure that each feature and functionality behaves as intended and identify discrepancies.
- Exploratory testing – involves unscripted testing where QA engineers explore the software’s functionalities, probing for unexpected behaviors, glitches, or inconsistencies.
- Regression testing – QA engineers retest previously validated aspects of the software after changes to ensure that the bugs were fixed and new code has not introduced new defects.
- Boundary and stress testing – QA engineers push the software to its limits by inputting extreme values or overwhelming it with excessive loads, aiming to identify potential vulnerabilities or performance-related bugs.
- Compatibility testing – they test the software on various platforms, browsers, and devices to ensure consistent behavior across different environments.
Upon gaining deeper experience, QA engineers can even predict where issues are likely to occur and go straight to the high-risk areas.
How to Tell It’s a Bug?
“It’s not a bug. It’s a feature.” A lovely joke with a lot of truth. Distinguishing between a legitimate bug and an intended feature or user error can sometimes be challenging.
Deviation from Specifications
If the observed behavior contradicts the documented requirements, there’s a strong possibility of a bug causing the inconsistency.
Example: an e-commerce website supposed to display product prices in USD shows them in a different currency.
Consistency of an Issue
If the issue occurs consistently under specific conditions and cannot be attributed to user actions, it’s likely a bug.
Example: a video editing software crashes every time a user tries to export a video file, regardless of the content being edited.
Unintended Outcomes
When the software produces outcomes that are unexpected, illogical, or inconsistent with its intended behavior, it’s indicative of a bug.
Example: a button opens the wrong form or takes a user to a wrong page.
Comparison with Previous Versions
Comparing the current behavior with previous software versions can reveal anomalies that point to the presence of a bug.
Example: in an updated version of a mobile game, characters move more slowly than they did in the previous version without any intentional design changes.
Reproducibility
Bugs are reproducible; if the same set of actions reliably triggers the issue, it’s likely a bug.
Example: a software application consistently crashes when a user attempts to upload a file larger than a certain size.
External Factors
Network connectivity, hardware failures, or third-party service disruptions may also cause functional disruptions (in this case, there’s no bug).
Example: a mobile app seems unresponsive, but the cause is traced back to poor network connectivity rather than an inherent software flaw.
Logs and Error Messages
Error messages, log files, and console outputs can provide valuable insights into the root cause of unexpected behaviors.
Example: a web application displays an error message indicating a database connection failure when users attempt to log in.
User Feedback
User reports and feedback often highlight patterns of unusual behavior that may indicate the presence of a bug.
Example: several users of a software application report that it freezes when they attempt to print a document.
How to Report a Bug?
Accurate bug reporting is essential for developers to understand, replicate, and resolve issues effectively. When reporting a bug, QA specialists need to:
- Detail the exact steps that led to the bug’s occurrence, including any specific inputs or actions taken.
- Note the operating system, browser, device, and any other relevant environment details in which the bug occurred.
- Clearly describe the bug’s symptoms (manifestations), such as error messages, crashes, or unexpected behaviors.
- Present visual aids like screenshots or log files to help developers visualize the issue and diagnose the bug faster.
Bug Classification by Severity
Bugs come in various forms and degrees of severity. And QA engineers need to identify and correctly assign the severity level to a bug to resolve it quickly. Consider these examples:
- Blocker – the login screen crashes immediately upon launching the application, rendering the software unusable.
- Critical bug – login screen that consistently crashes the application, preventing users from accessing the software.
- Major bug – an e-commerce website that fails to process orders, leading to loss of potential sales.
- Minor bug – a typo in a user interface label that doesn’t impact functionality but affects the software’s professionalism.
- Low/trivial – a button in the settings menu has a slightly misaligned icon, but it still functions correctly when clicked.
Identifying the severity of a bug is an essential part of the bug tracking and management process. Severity refers to a bug’s impact on the software’s functionality and user experience. Here’s how QA experts can determine the severity of a bug:
- Functional impact – determine how severely the bug affects the software’s core functionality. Does it prevent users from accomplishing critical tasks, or is it a minor inconvenience?
- User impact – find out how the issue influences end-users. Does the bug cause data loss, crashes, or other critical matters that significantly disrupt their experience?
- Workaround availability – define any viable workarounds for the bug. A severe bug with no available workaround may have higher severity.
- Scope of affected users – assess the number of users or systems affected by the bug. A bug affecting a large user base might have higher severity.
- Data integrity – consider whether the bug compromises the accuracy or integrity of data processed by the software.
- Regularity of occurrence – identify if the bug occurs consistently or intermittently. Consistent occurrences may indicate higher severity.
- Legal or regulatory impact – if the bug violates legal or regulatory requirements, it may have higher severity.
Now to another critical error characteristic – priority. It’s the order in which a bug should be addressed relative to other issues/tasks. Priority is mainly affected by a defect’s impact on the users and the available resources needed to fix it. So, for example, if there are two critical bugs, the first to be amended is determined by its priority.
What Are Bug Fixes?
When it comes to bug elimination, the process involves identifying, addressing, and rectifying issues to ensure that the software operates as intended.
Who Is Responsible for Bug Fixing?
Bug fixing is a collaborative effort that typically involves multiple stakeholders, including:
- Developers, who are at the forefront of bug fixing as they analyze and address the underlying code issues. They write and implement the corrective code changes.
- QA engineers, who play a pivotal role in identifying and documenting bugs during testing. Their comprehensive testing efforts help ensure that bugs are detected before software reaches end-users.
- Product managers, who prioritize bugs based on their impact on the user experience and business objectives. They help decide which bugs should be addressed immediately and which can be deferred.
- End-users, who often report bugs they encounter while using the software. Their feedback contributes to bug detection and helps in prioritizing fixes.
- Customer support teams, who gather insights from users’ bug reports and experiences. They help validate the existence and impact of bugs.
How to Identify That Something Needs Fixing?
Detecting the need for bug fixes involves vigilant observation and data-driven analysis.
- User reports – user complaints, error messages, and feedback are valuable indicators of potential bugs.
- Unintended behaviors – unexpected, inconsistent, or erroneous behaviors observed during software use may signal the presence of bugs.
- Performance issues – sluggish performance, frequent crashes, or excessive resource consumption can point to underlying issues.
- Regression testing – comparing current software behavior against previous versions can reveal deviations that need attention.
- Monitoring and analytics – utilizing monitoring tools and analyzing user analytics can highlight patterns of abnormal behavior.
How to Manage Bug Fixes?
Effectively managing bug fixes requires a systematic approach. It’s a complicated procedure that goes beyond “if you see something – scream”. To do it properly, QA specialists and developers need to:
- Employ bug-tracking tools to document and organize bugs, assign ownership, track progress, and communicate updates.
- Prioritize bug fixes based on severity and priority to structure the workload.
- Use version control systems to manage code changes, ensuring bug fixes are appropriately integrated and tracked.
- Rigorously test bug fixes to confirm they resolve the issue without introducing new problems.
- Integrate bug fixes into planned releases and updates, considering their impact on project timelines.
Can Bugs Be Ignored?
While most bugs should be addressed, there are scenarios where some might be put off, ignored, or not fixed.
- Minor and low-impact bugs – bugs with minimal impact on the user experience or business operations may be deferred to prioritize more critical issues.
- Workarounds available – bugs with known workarounds might be deprioritized if the workaround is practical and feasible.
- Compatibility and legacy systems – bugs affecting outdated or unsupported platforms may not warrant immediate fixes.
- Resource constraints – in cases of limited resources or tight schedules, low-impact bugs might be temporarily set aside.
To Sum Up
The bug paradox is fascinating. Some hate defects as they denote failure. Some love them, as they also mean a job well done. Still, there’s a single certainty – mistakes help us grow. So let’s appreciate each bug and each mistake we make. They’re here to make us better.